WASHINGTON — An ideological battle is brewing in Congress over a tiny government program most people have never heard of, targeted by Tea Party-inspired Republicans in a largely symbolic gesture against "corporate welfare."

House conservatives held an event this week urging the death of the Export-Import Bank, an 81-year-old agency that provides loans and loan guarantees for projects involving U.S companies doing business overseas.

The bank's charter expires at the end of June unless Congress acts to extend it, which gives opponents a huge advantage. "All Congress has to do is what is does best: nothing," said Rep. Jim Jordan, R-Ohio, head of the House Freedom Caucus, in an interview with USA TODAY.

The Ex-Im Bank has become a favorite target of Tea Party groups who argue that it is a prime example of "crony capitalism" — government assistance for well-connected companies. The bank argues that is not true, noting that 90% of the companies it works with are small businesses, although about 75% of the value of its loans go to larger firms.

The idea behind the bank is that is a U.S. company wants to sell an airplane or other product to a foreign buyer, and no private lender will provide financing, the Ex-Im bank can provide the loan or guarantee the loan, allowing completion of the sale.

An array of business groups such as the U.S. Chamber of Commerce say the bank actually serves a vital role by leveling the playing field with other nations that provide government financing for their exporters. The bank said it authorized 3,700 projects that "created or sustained" 164,000 U.S. jobs in its annual report for 2014. The chamber has launched an ad blitz across the country urging viewers to call their lawmakers and urge support of the bank.

While the bank authorizes loans worth billions — $20.5 billion in 2014 — the cost to taxpayers are negligible. The bank has an annual budget of around $100 million, but it charges fees on its loans and returns money to the U.S. Treasury every year. In 2014, the bank returned $675 million, bank president Fred Hochberg said at a hearing Tuesday.

Hochberg rejected the notion that the bank is providing "corporate welfare," because welfare "implies taking money from one group of people and handing to somebody else. We have actually customers, clients of the bank, giving us money for a service. We render the service and then the excess we send to the taxpayer. So, it goes the exact opposite direction."

Those profits are an illusion based on a government accounting system that ignores the true market value of risks, said Rep. Jeb Hensarling, R-Texas, chairman of the House Financial Services Committee, which has authority over the bank. The Congressional Budget Office has reported that using private-sector accounting methods, the bank would operate at a loss of about $200 million a year.

Opponents are gaining ground, Hensarling says. "Momentum is in our favor because ultimately the American people do not want privilege and subsidy. What they want is freedom and opportunity and that's what this fight is all about," he said Tuesday.

The bank has also been a target of criticism because of a series of scandals, including a bank official being charged with bribery last month for allegedly accepting cash and other gifts in exchange for helping companies get financing for projects.

But not all Republicans agree the bank should expire. House Speaker John Boehner, R-Ohio, said in April that "there are thousands of jobs on the line that would disappear pretty quickly if the Ex-Im Bank were to disappear."

Another supporter is Sen. Lindsey Graham, a South Carolina Republican and likely presidential candidate.

"The fact that you would let the bank expire because of some ideological jihad on our side makes no sense to me," Graham said in a Senate speech Tuesday. "To the people who are trying to make this the scalp for conservatism, I think you lost your way."

Graham is alone among GOP presidential contenders in his support for the bank.

Graham and Sen. Maria Cantwell, D-Wash., are trying to add the Ex-Im Bank extension to a key trade bill the White House is trying to push through Congress.

Ending the bank's charter would not have an immediate impact, Jordan said. Existing loans would remain in place, he said, and the bank's operations would wind down over several years.

Democrats are united in support of the bank.

Rep. Maxine Waters of California, the top Democrat on Hensarling's committee, said Wednesday that she was disturbed that the fate of the bank remained uncertain. She accused Hensarling of "a continuation of the intransigence that has already bred uncertainty and instability among the thousands of businesses who rely on the Export-Import Bank to create jobs, grow their businesses and stay competitive."